Transmission dynamics of dengue with asymptomatic infection and a case study in Bangladesh

Dengue is a serious global public health crisis. The majority of dengue infections are asymptomatic, which makes disease control difficult. In this paper, a host-vector model considering asymptomatic infection and extrinsic and intrinsic incubation periods is developed to simulate the transmission pattern of dengue. The basic reproduction number is calculated by using the renewal equation method. The global threshold dynamics is established by constructing suitable Lyapunov functionals and using LaSalle's invariance principle. The model is validated by fitting it to 2023 dengue epidemic data in Bangladesh. The fitting results show that the basic reproduction number is 4.1621 in the absence of control measures, in which contributions of asymptomatic infection and symptomatic infection account for 65% and 35%, respectively. In addition, through sensitivity analysis and numerical simulations, the effects of control measures and asymptomatic infection on basic reproduction number and transmission dynamics of dengue are clarified. The results show that (1) when the infectivity of asymptomatic individuals is more than 0.6 times that of symptomatic individuals, it is necessary to take measures to control the transmission risk of asymptomatic individuals; (2) the mortality rate of mosquito is the most critical factor in controlling dengue; (3) the mosquito density threshold for preventing mass transmission of dengue is 0.5199.